Diarylmethylidene piperidine derivatives, preparations thereof and uses thereof as opoid receptors ligands

ABSTRACT

Compounds of general formula: (I) wherein R 1 , R 2 , R 3  and A are as defined in the specification, as well as salts, enantiomers thereof and pharmaceutical compositions including the compounds are prepared. They are useful in therapy, in particular in the treatment of pain and anxiety.

FIELD OF THE INVENTION

The present invention is directed to novel compounds, to a process fortheir preparation, their use and pharmaceutical compositions comprisingthe novel compounds. The novel compounds are useful in therapy, and inparticular for the treatment of pain, anxiety and functionalgastrointestinal disorders.

BACKGROUND OF THE INVENTION

The receptor has been identified as having a role in many bodilyfunctions such as circulatory and pain systems. Ligands for the δreceptor may therefore find potential use as analgesics, and/or asantihypertensive agents. Ligands for the δ receptor have also been shownto possess immunomodulatory activities.

The identification of at least three different populations of opioidreceptors (μ, δ and κ) is now well established and all three areapparent in both central and peripheral nervous systems of many speciesincluding man. Analgesia has been observed in various animal models whenone or more of these receptors has been activated.

With few exceptions, currently available selective opioid δ ligands arepeptidic in nature and are unsuitable for administration by systemicroutes. One example of a non-peptidic δ-agonist is SNC80 (Bilsky E. J.et al., Journal of Pharmacology and Experimental Therapeutics, 273(1),pp. 359-366 (1995)).

Many δ agonist compounds that have been identified in the prior art havemany disadvantages in that they suffer from poor pharmacokinetics andare not analgesic when administered by systemic routes. Also, it hasbeen documented that many of these δ agonist compounds show significantconvulsive effects when administered systemically.

U.S. Pat. No. 6,187,792 to Delorme et al. describes some 5-agonists.

However, there is still a need for improved δ-agonists.

DESCRIPTION OF THE INVENTION

Thus, the problem underlying the present invention was to find newanalgesics having improved analgesic effects, but also with an improvedside-effect profile over current μ agonists, as well as having improvedsystemic efficacy.

We have now found certain compounds that exhibit surprisingly improvedproperties, i.e. improved δ agonist potency, in vivo potency,pharmacokinetic, bioavailability, in vitro stability and/or lowertoxicity.

Accordingly, it is an objective of certain embodiments of the presentinvention to provide improved δ receptor ligands.

Unless specified otherwise within this specification, the nomenclatureused in this specification generally follows the examples and rulesstated in Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F,and H, Pergamon Press, Oxford, 1979, which is incorporated by referencesherein for its exemplary chemical structure names and rules on namingchemical structures. Optionally, a name of a compound may be generatedusing a chemical naming program: ACD/ChemSketch, Version 5.09/September2001, Advanced Chemistry Development, Inc., Toronto, Canada.

The term “C_(m-n)” or “C_(m-n) group” used alone or as a prefix, refersto any group having m to n carbon atoms.

The term “hydrocarbon” used alone or as a suffix or prefix, refers toany structure comprising only carbon and hydrogen atoms up to 14 carbonatoms.

The term “hydrocarbon radical” or “hydrocarbyl” used alone or as asuffix or prefix, refers to any structure as a result of removing one ormore hydrogens from a hydrocarbon.

The term “alkyl” used alone or as a suffix or prefix, refers tomonovalent straight or branched chain hydrocarbon radicals comprising 1to about 12 carbon atoms. Unless otherwise specified, “alkyl” generalincludes both saturated alkyl and unsaturated alkyl.

The term “alkylene” used alone or as suffix or prefix, refers todivalent straight or branched chain hydrocarbon radicals comprising 1 toabout 12 carbon atoms, which serves to link two structures together.

The term “alkenyl” used alone or as suffix or prefix, refers to amonovalent straight or branched chain hydrocarbon radical having atleast one carbon-carbon double bond and comprising at least 2 up toabout 12 carbon atoms.

The term “alkynyl” used alone or as suffix or prefix, refers to amonovalent straight or branched chain hydrocarbon radical having atleast one carbon-carbon triple bond and comprising at least 2 up toabout 12 carbon atoms.

The term “cycloalkyl,” used alone or as suffix or prefix, refers to amonovalent ring-containing hydrocarbon radical comprising at least 3 upto about 12 carbon atoms.

The term “cycloalkenyl” used alone or as suffix or prefix, refers to amonovalent ring-containing hydrocarbon radical having at least onecarbon-carbon double bond and comprising at least 3 up to about 12carbon atoms.

The term “cycloalkynyl” used alone or as suffix or prefix, refers to amonovalent ring-containing hydrocarbon radical having at least onecarbon-carbon triple bond and comprising about 7 up to about 12 carbonatoms.

The term “aryl” used alone or as suffix or prefix, refers to amonovalent hydrocarbon radical having one or more polyunsaturated carbonrings having aromatic character, (e.g., 4n+2 delocalized electrons) andcomprising 5 up to about 14 carbon atoms.

The term “arylene” used alone or as suffix or prefix, refers to adivalent hydrocarbon radical having one or more polyunsaturated carbonrings having aromatic character, (e.g., 4n+2 delocalized electrons) andcomprising 5 up to about 14 carbon atoms, which serves to links twostructures together.

The term “heterocycle” used alone or as a suffix or prefix, refers to aring-containing structure or molecule having one or more multivalentheteroatoms, independently selected from N, O and S, as a part of thering structure and including at least 3 and up to about 20 atoms in thering(s). Heterocycle may be saturated or unsaturated, containing one ormore double bonds, and heterocycle may contain more than one ring. Whena heterocycle contains more than one ring, the rings may be fused orunfused. Fused rings generally refer to at least two rings share twoatoms therebetween. Heterocycle may have aromatic character or may nothave aromatic character.

The term “heteroalkyl” used alone or as a suffix or prefix, refers to aradical formed as a result of replacing one or more carbon atom of analkyl with one or more heteroatoms selected from N, O and S.

The term “heteroaromatic” used alone or as a suffix or prefix, refers toa ring-containing structure or molecule having one or more multivalentheteroatoms, independently selected from N, O and S, as a part of thering structure and including at least 3 and up to about 20 atoms in thering(s), wherein the ring-containing structure or molecule has anaromatic character (e.g., 4n+2 delocalized electrons).

The term “heterocyclic group,” “heterocyclic moiety,” “heterocyclic,” or“heterocyclo” used alone or as a suffix or prefix, refers to a radicalderived from a heterocycle by removing one or more hydrogens therefrom.

The term “heterocyclyl” used alone or as a suffix or prefix, refers amonovalent radical derived from a heterocycle by removing one hydrogentherefrom.

The term “heterocyclylene” used alone or as a suffix or prefix, refersto a divalent radical derived from a heterocycle by removing twohydrogens therefrom, which serves to links two structures together.

The term “heteroaryl” used alone or as a suffix or prefix, refers to aheterocyclyl having aromatic character.

The term “heterocylcoalkyl” used alone or as a suffix or prefix, refersto a heterocyclyl that does not have aromatic character.

The term “heteroarylene” used alone or as a suffix or prefix, refers toa heterocyclylene having aromatic character.

The term “heterocycloalkylene” used alone or as a suffix or prefix,refers to a heterocyclylene that does not have aromatic character.

The term “six-membered” used as prefix refers to a group having a ringthat contains six ring atoms.

The term “five-membered” used as prefix refers to a group having a ringthat contains five ring atoms.

A five-membered ring heteroaryl is a heteroaryl with a ring having fivering atoms wherein 1, 2 or 3 ring atoms are independently selected fromN, O and S.

Exemplary five-membered ring heteroaryls are thienyl, furyl, pyrrolyl,imidazolyl, thiazolyl, oxazolyl, pyrazolyl, isothiazolyl, isoxazolyl,1,2,3-triazolyl, tetrazolyl, 1,2,3-thiadiazolyl, 1,2,3-oxadiazolyl,1,2,4-triazolyl, 1,2,4-thiadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-triazolyl,1,3,4-thiadiazolyl, and 1,3,4-oxadiazolyl.

A six-membered ring heteroaryl is a heteroaryl with a ring having sixring atoms wherein 1, 2 or 3 ring atoms are independently selected fromN, O and S.

Exemplary six-membered ring heteroaryls are pyridyl, pyrazinyl,pyrimidinyl, triazinyl and pyridazinyl.

The term “substituted” used as a prefix refers to a structure, moleculeor group, wherein one or more hydrogens are replaced with one or moreC₁₋₁₂hydrocarbon groups, or one or more chemical groups containing oneor more heteroatoms selected from N, O, S, F, Cl, Br, I, and P.Exemplary chemical groups containing one or more heteroatoms includeheterocyclyl, —NO₂, —OR, —Cl, —Br, —I, —F, —CF₃, —C(═O)R, —C(═O)OH,—NH₂, —SH, —NHR, —NR₂, —SR, —SO₃H, —SO₂R, —S(═O)R, —CN, —OH, —C(═O)OR,—C(═O)NR₂, —NRC(═O)R, oxo (═O), imino (═NR), thio (═S), and oximino(═N—OR), wherein each “R” is a C₁₋₁₂hydrocarbyl. For example,substituted phenyl may refer to nitrophenyl, pyridylphenyl,methoxyphenyl, chlorophenyl, aminophenyl, etc., wherein the nitro,pyridyl, methoxy, chloro, and amino groups may replace any suitablehydrogen on the phenyl ring.

The term “substituted” used as a suffix of a first structure, moleculeor group, followed by one or more names of chemical groups refers to asecond structure, molecule or group, which is a result of replacing oneor more hydrogens of the first structure, molecule or group with the oneor more named chemical groups. For example, a “phenyl substituted bynitro” refers to nitrophenyl.

The term “optionally substituted” refers to both groups, structures, ormolecules that are substituted and those that are not substituted.

Heterocycle includes, for example, monocyclic heterocycles such as:aziridine, oxirane, thiirane, azetidine, oxetane, thietane, pyrrolidine,pyrroline, imidazolidine, pyrazolidine, pyrazoline, dioxolane, sulfolane2,3-dihydrofuran, 2,5-dihydrofuran tetrahydrofuran, thiophane,piperidine, 1,2,3,6-tetrahydro-pyridine, piperazine, morpholine,thiomorpholine, pyran, thiopyran, 2,3-dihydropyran, tetrahydropyran,1,4-dihydropyridine, 1,4-dioxane, 1,3-dioxane, dioxane, homopiperidine,2,3,4,7-tetrahydro-1H-azepine homopiperazine, 1,3-dioxepane,4,7-dihydro-1,3-dioxepin, and hexamethylene oxide.

In addition, heterocycle includes aromatic heterocycles, for example,pyridine, pyrazine, pyrimidine, pyridazine, thiophene, furan, furazan,pyrrole, imidazole, thiazole, oxazole, pyrazole, isothiazole, isoxazole,1,2,3-triazole, tetrazole, 1,2,3-thiadiazole, 1,2,3-oxadiazole,1,2,4-triazole, 1,2,4-thiadiazole, 1,2,4-oxadiazole, 1,3,4-triazole,1,3,4-thiadiazole, and 1,3,4-oxadiazole.

Additionally, heterocycle encompass polycyclic heterocycles, forexample, indole, indoline, isoindoline, quinoline, tetrahydroquinoline,isoquinoline, tetrahydroisoquinoline, 1,4-benzodioxan, coumarin,dihydrocoumarin, benzofuran, 2,3-dihydrobenzofuran, isobenzofuran,chromene, chroman, isochroman, xanthene, phenoxathiin, thianthrene,indolizine, isoindole, indazole, purine, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, phenanthridine,perimidine, phenanthroline, phenazine, phenothiazine, phenoxazine,1,2-benzisoxazole, benzothiophene, benzoxazole, benzthiazole,benzimidazole, benztriazole, thioxanthine, carbazole, carboline,acridine, pyrolizidine, and quinolizidine.

In addition to the polycyclic heterocycles described above, heterocycleincludes polycyclic heterocycles wherein the ring fusion between two ormore rings includes more than one bond common to both rings and morethan two atoms common to both rings. Examples of such bridgedheterocycles include quinuclidine, diazabicyclo[2.2.1]heptane and7-oxabicyclo[2.2.1]heptane.

Heterocyclyl includes, for example, monocyclic heterocyclyls, such as:aziridinyl, oxiranyl, thiiranyl, azetidinyl, oxetanyl, thietanyl,pyrrolidinyl, pyrrolinyl, imidazolidinyl, pyrazolidinyl, pyrazolinyl,dioxolanyl, sulfolanyl, 2,3-dihydrofuranyl, 2,5-dihydrofuranyl,tetrahydrofuranyl, thiophanyl, piperidinyl, 1,2,3,6-tetrahydropyridinyl,piperazinyl, morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl,2,3-dihydropyranyl, tetrahydropyranyl, 1,4-dihydropyridinyl,1,4-dioxanyl, 1,3-dioxanyl, dioxanyl, homopiperidinyl,2,3,4,7-tetrahydro-1H-azepinyl, homopiperazinyl, 1,3-dioxepanyl,4,7-dihydro-1,3-dioxepinyl, and hexamethylene oxidyl.

In addition, heterocyclyl includes aromatic heterocyclyls or heteroaryl,for example, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, thienyl,furyl, furazanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, pyrazolyl,isothiazolyl, isoxazolyl, 1,2,3-triazolyl, tetrazolyl,1,2,3-thiadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-triazolyl,1,2,4-thiadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-triazolyl,1,3,4-thiadiazolyl, and 1,3,4 oxadiazolyl.

Additionally, heterocyclyl encompasses polycyclic heterocyclyls(including both aromatic or non-aromatic), for example, indolyl,indolinyl, isoindolinyl, quinolinyl, tetrahydroquinolinyl,isoquinolinyl, tetrahydroisoquinolinyl, 1,4-benzodioxanyl, coumarinyl,dihydrocoumarinyl, benzofuranyl, 2,3-dihydrobenzofuranyl,isobenzofuranyl, chromenyl, chromanyl, isochromanyl, xanthenyl,phenoxathiinyl, thianthrenyl, indolizinyl, isoindolyl, indazolyl,purinyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl,cinnolinyl, pteridinyl, phenanthridinyl, perimidinyl, phenanthrolinyl,phenazinyl, phenothiazinyl, phenoxazinyl, 1,2-benzisoxazolyl,benzothiophenyl, benzoxazolyl, benzthiazolyl, benzimidazolyl,benztriazolyl, thioxanthinyl, carbazolyl, carbolinyl, acridinyl,pyrolizidinyl, and quinolizidinyl.

In addition to the polycyclic heterocyclyls described above,heterocyclyl includes polycyclic heterocyclyls wherein the ring fusionbetween two or more rings includes more than one bond common to bothrings and more than two atoms common to both rings. Examples of suchbridged heterocycles include quinuclidinyl, diazabicyclo[2.2.1]heptyl;and 7-oxabicyclo[2.2.1]heptyl.

The term “alkoxy” used alone or as a suffix or prefix, refers toradicals of the general formula —O—R, wherein R is selected from ahydrocarbon radical. Exemplary alkoxy includes methoxy, ethoxy, propoxy,isopropoxy, butoxy, t-butoxy, isobutoxy, cyclopropylmethoxy, allyloxy,and propargyloxy.

The term “amine” or “amino” used alone or as a suffix or prefix, refersto radicals of the general formula —NRR′, wherein R and R′ areindependently selected from hydrogen or a hydrocarbon radical.

“Acyl” used alone, as a prefix or suffix, means —C(═O)—R, wherein R isan optionally substituted hydrocarbyl, hydrogen, amino or alkoxy. Acylgroups include, for example, acetyl, propionyl, benzoyl, phenyl acetyl,carboethoxy, and dimethylcarbamoyl.

Halogen includes fluorine, chlorine, bromine and iodine.

“Halogenated,” used as a prefix of a group, means one or more hydrogenson the group is replaced with one or more halogens.

“RT” or “rt” means room temperature.

A first ring group being “fused” with a second ring group means thefirst ring and the second ring share at least two atoms therebetween.

“Link,” “linked,” or “linking,” unless otherwise specified, meanscovalently linked or bonded.

In one aspect, the invention provides a compound of formula I, apharmaceutically acceptable salt thereof, solvates thereof,diastereomers thereof, enantiomers thereof, and mixtures thereof:

wherein

R¹ is selected from hydrogen, C₁₋₆alkyl-O—C(═O)—, optionally substitutedC₁₋₆alkyl, optionally substituted C₃₋₆cycloalkyl, optionally substitutedC₆₋₁₀aryl, optionally substituted C₂₋₉heterocyclyl, optionallysubstituted C₆₋₁₀aryl-C₁₋₃alkyl and optionally substitutedC₂₋₉heterocyclyl-C₁₋₃alkyl;

R² and R³ are, independently, selected from hydrogen, optionallysubstituted C₁₋₆alkyl and optionally substituted C₃₋₆cycloalkyl; and

A is selected from:

wherein

R⁴ is selected from optionally substituted C₃₋₆alkyl, optionallysubstituted C₃₋₈cycloalkyl, optionally substituted C₆₋₁₀aryl, optionallysubstituted C₂₋₉heterocyclyl, optionally substitutedC₆₋₁₀aryl-C₁₋₆alkyl, and optionally substitutedC₂₋₉heterocyclyl-C₁₋₆alkyl;

R⁵ is a divalent group selected from optionally substituted C₆₋₁₀arylene, optionally substituted C₂₋₉heterocyclylene, optionallysubstituted C₅₋₆cycloalkylene and optionally substituted C₂₋₄alkylene,and

D is selected from a single bond, —CH₂—, —S—, —O—, —S(═O)—, —S(═O)₂—,—NH—, —NR⁶—, —C(═O)—, —CHR⁶—, and —CR⁶R⁷—, wherein R⁶ and R⁷ areindependently C₁₋₆alkyl, C⁶⁻¹⁰aryl or C₂₋₉heterocyclyl.

Particularly, the compounds of the present invention are those offormula I, wherein R¹ is selected from hydrogen, C₁₋₆alkyl-O—C(═O)—,optionally substituted C₁₋₆alkyl, and optionally substitutedC₃₋₆cycloalkyl;

R² and R³ are ethyl;

R⁴ is selected from phenyl, C₃₋₅heterocyclyl, phenyl-C₁₋₃alkyl,C₃₋₅heterocyclyl-C₁₋₃alkyl, C₃₋₆cycloalkyl, andC₃₋₆cycloalkyl-C₁₋₃alkyl, wherein R⁴ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆alkoxy, chloro, fluoro, bromo, and iodo;

R⁵ is a divalent group selected from ortho-phenylene,ortho-C₃₋₅heterocyclylene and ortho-C₅₋₆cycloalkylene, wherein R⁵ isoptionally substituted with one or more groups selected from C₁₋₆alkyl,halogenated C₁₋₆alkyl, —NO₂, —CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo,and iodo; and

D is selected from a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂—, —NH—,and —C(═O)—.

More particularly, the compounds of the present invention are those offormula I, wherein R¹ is selected from hydrogen and C₁₋₆alkyl-O—C(═O)—;

R² and R³ are ethyl;

R⁴ is selected from phenyl-C₁₋₃alkyl, C₃₋₆cycloalkyl-C₁₋₃alkyl,C₃₋₆cycloalkyl, and phenyl, wherein R⁴ is optionally substituted withone or more groups selected from methyl, fluoro, chloro, bromo and iodo;

R⁵ is selected from ortho-phenylene, ortho-pyridylene,1,2-cyclopentylene and 1,2-cyclohexylene; and

D is selected from a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂— and—C(═O)—.

Most particularly, the compounds of the present invention are those offormula I, wherein

R¹ is selected from hydrogen and t-butyl-O—C(═O)—;

R² and R³ are ethyl;

R⁴ is selected from phenyl, methylphenyl, fluorophenyl, phenylethyl,cyclohexyl, fluorobenzyl, methylbenzyl, benzyl and cyclopentyl;

R⁵ is ortho-phenylene; and

D is selected from a single bond and —S—.

It will be understood that when compounds of the present inventioncontain one or more chiral centers, the compounds of the invention mayexist in, and be isolated as, enantiomeric or diastereomeric forms, oras a racemic mixture. The present invention includes any possibleenantiomers, diastereomers, racemates or mixtures thereof, of a compoundof Formula I. The optically active forms of the compound of theinvention may be prepared, for example, by chiral chromatographicseparation of a racemate, by synthesis from optically active startingmaterials or by asymmetric synthesis based on the procedures describedthereafter.

It will also be appreciated that certain compounds of the presentinvention may exist as geometrical isomers, for example E and Z isomersof alkenes. The present invention includes any geometrical isomer of acompound of Formula I. It will further be understood that the presentinvention encompasses tautomers of the compounds of the formula I.

It will also be understood that certain compounds of the presentinvention may exist in solvated, for example hydrated, as well asunsolvated forms. It will further be understood that the presentinvention encompasses all such solvated forms of the compounds of theformula I.

Within the scope of the invention are also salts of the compounds of theformula I. Generally, pharmaceutically acceptable salts of compounds ofthe present invention may be obtained using standard procedures wellknown in the art, for example by reacting a sufficiently basic compound,for example an alkyl amine with a suitable acid, for example, HCl oracetic acid, to afford a physiologically acceptable anion. It may alsobe possible to make a corresponding alkali metal (such as sodium,potassium, or lithium) or an alkaline earth metal (such as a calcium)salt by treating a compound of the present invention having a suitablyacidic proton, such as a carboxylic acid or a phenol with one equivalentof an alkali metal or alkaline earth metal hydroxide or alkoxide (suchas the ethoxide or methoxide), or a suitably basic organic amine (suchas choline or meglumine) in an aqueous medium, followed by conventionalpurification techniques.

In one embodiment, the compound of formula I above may be converted to apharmaceutically acceptable salt or solvate thereof, particularly, anacid addition salt such as a hydrochloride, hydrobromide, phosphate,acetate, fumarate, maleate, tartrate, citrate, methanesulphonate orp-toluenesulphonate.

The novel compounds of the present invention are useful in therapy,especially for the treatment of various pain conditions such as chronicpain, neuropathic pain, acute pain, cancer pain, pain caused byrheumatoid arthritis, migraine, visceral pain etc. This list shouldhowever not be interpreted as exhaustive.

Compounds of the invention are useful for the treatment of diarrhoea,depression, anxiety and stress-related disorders such as post-traumaticstress disorders, panic disorder, generalized anxiety disorder, socialphobia, and obsessive compulsive disorder, urinary incontinence,premature ejaculation, various mental illnesses, cough, lung oedema,various gastro-intestinal disorders, e.g. constipation, functionalgastrointestinal disorders such as Irritable Bowel Syndrome andFunctional Dyspepsia, Parkinson's disease and other motor disorders,traumatic brain injury, stroke, cardioprotection following miocardialinfarction, spinal injury and drug addiction, including the treatment ofalcohol, nicotine, opioid and other drug abuse and for disorders of thesympathetic nervous system for example hypertension.

Compounds of the invention are useful as immunomodulators, especiallyfor autoimmune diseases, such as arthritis, for skin grafts, organtransplants and similar surgical needs, for collagen diseases, variousallergies, for use as anti-tumour agents and anti viral agents.

Compounds of the invention are useful in disease states wheredegeneration or dysfunction of opioid receptors is present or implicatedin that paradigm. This may involve the use of isotopically labelledversions of the compounds of the invention in diagnostic techniques andimaging applications such as positron emission tomography (PET).

Compounds of the invention are useful as an analgesic agent for useduring general anaesthesia and monitored anaesthesia care. Combinationsof agents with different properties are often used to achieve a balanceof effects needed to maintain the anaesthetic state (e.g. amnesia,analgesia, muscle relaxation and sedation). Included in this combinationare inhaled anaesthetics, hypnotics, anxiolytics, neuromuscular blockersand opioids.

Within the scope of the invention is the use of any compound of formulaI as defined above for the manufacture of a medicament.

Also within the scope of the invention is the use of any compound of theinvention for the manufacture of a medicament for the therapy of painincluding, but not limited to: acute pain, chronic pain, neuropathicpain, back pain, cancer pain, and visceral pain.

Also within the scope of the invention is the use of any compound of theinvention for the manufacture of a medicament for the therapy ofanxiety.

Also within the scope of the invention is the use of any of thecompounds of the present invention, for the manufacture of a medicamentfor the treatment of any of the conditions discussed above.

A further aspect of the invention is a method for the treatment of asubject suffering from any of the conditions discussed above, whereby aneffective amount of a compound of the present invention, is administeredto a patient in need of such treatment.

Thus, the invention provides a compound of formula I, orpharmaceutically acceptable salt or solvate thereof, as hereinbeforedefined for use in therapy.

In the context of the present specification, the term “therapy” alsoincludes “prophylaxis” unless there are specific indications to thecontrary. The term “therapeutic” and “therapeutically” should becontrued accordingly. The term “therapy” within the context of thepresent invention further encompasses to administer an effective amountof a compound of the present invention, to mitigate either apre-existing disease state, acute or chronic, or a recurring condition.This definition also encompasses prophylactic therapies for preventionof recurring conditions and continued therapy for chronic disorders.

In use for therapy in a warm-blooded animal such as a human, thecompound of the invention may be administered in the form of aconventional pharmaceutical composition by any route including orally,intramuscularly, subcutaneously, topically, intranasally,intraperitoneally, intrathoracially, intravenously, epidurally,intrathecally, intracerebroventricularly and by injection into thejoints.

In one embodiment of the invention, the route of administration may beorally, intravenously or intramuscularly.

The dosage will depend on the route of administration, the severity ofthe disease, age and weight of the patient and other factors normallyconsidered by the attending physician, when determining the individualregimen and dosage level at the most appropriate for a particularpatient.

Additionally, there is provided a pharmaceutical composition comprisinga compound of Formula I, solvates thereof, or a pharmaceuticallyacceptable salt thereof, in association with a pharmaceuticallyacceptable carrier.

Particularly, there is provided a pharmaceutical composition comprisinga compound of Formula I, solvates thereof, or a pharmaceuticallyacceptable salt thereof, in association with a pharmaceuticallyacceptable carrier for therapy, more particularly for therapy of painand anxiety.

Further, there is provided a pharmaceutical composition comprising acompound of Formula I, solvates thereof, or a pharmaceuticallyacceptable salt thereof, in association with a pharmaceuticallyacceptable carrier use in any of the conditions discussed above.

For preparing pharmaceutical compositions from the compounds of thisinvention, inert, pharmaceutically acceptable carriers can be eithersolid and liquid. Solid form preparations include powders, tablets,dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substances, which may also act asdiluents, flavoring agents, solubilizers, lubricants, suspending agents,binders, or table disintegrating agents; it can also be an encapsulatingmaterial.

In powders, the carrier is a finely divided solid, which is in a mixturewith the finely divided compound of the invention, or the activecomponent. In tablets, the active component is mixed with the carrierhaving the necessary binding properties in suitable proportions andcompacted in the shape and size desired.

For preparing suppository compositions, a low-melting wax such as amixture of fatty acid glycerides and cocoa butter is first melted andthe active ingredient is dispersed therein by, for example, stirring.The molten homogeneous mixture in then poured into convenient sizedmoulds and allowed to cool and solidify.

Suitable carriers are magnesium carbonate, magnesium stearate, talc,lactose, sugar, pectin, dextrin, starch, tragacanth, methyl cellulose,sodium carboxymethyl cellulose, a low-melting wax, cocoa butter, and thelike.

The term composition is also intended to include the formulation of theactive component with encapsulating material as a carrier providing acapsule in which the active component (with or without other carriers)is surrounded by a carrier which is thus in association with it.Similarly, cachets are included.

Tablets, powders, cachets, and capsules can be used as solid dosageforms suitable for oral administration.

Liquid form compositions include solutions, suspensions, and emulsions.For example, sterile water or water propylene glycol solutions of theactive compounds may be liquid preparations suitable for parenteraladministration. Liquid compositions can also be formulated in solutionin aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolvingthe active component in water and adding suitable colorants, flavoringagents, stabilizers, and thickening agents as desired. Aqueoussuspensions for oral use can be made by dispersing the finely dividedactive component in water together with a viscous material such asnatural synthetic gums, resins, methyl cellulose, sodium carboxymethylcellulose, and other suspending agents known to the pharmaceuticalformulation art.

Depending on the mode of administration, the pharmaceutical compositionwill preferably include from 0.05% to 99% w (percent by weight), morepreferably from 0.10 to 50% w, of the compound of the invention, allpercentages by weight being based on total composition.

A therapeutically effective amount for the practice of the presentinvention may be determined, by the use of known criteria including theage, weight and response of the individual patient, and interpretedwithin the context of the disease which is being treated or which isbeing prevented, by one of ordinary skills in the art.

In a further aspect, the present invention provides a method ofpreparing the compounds of the present invention.

In one embodiment, the invention provides a process for preparing acompound of formula I, comprising:

reacting a compound of formula II with A-B(OR⁸)₂:

wherein R¹ is selected from hydrogen, C₁₋₆alkyl-O—C(═O)—, optionallysubstituted C₁₋₆alkyl, and optionally substituted C₃₋₆cycloalkyl;

R² and R³ are ethyl;

X is selected from I, Br and Cl;

R⁸ is selected from —H and C₁₋₆alkyl;

A is selected from:

wherein

R⁴ is selected from phenyl, C₃₋₅heterocyclyl, phenyl-C₁₋₃alkyl,C₃₋₅heterocyclyl-C₁₋₃alkyl, C₃₋₆cycloalkyl, andC₃₋₆cycloalkyl-C₁₋₃alkyl, wherein R⁴ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo, and iodo;

R⁵ is a divalent group selected from ortho-phenylene,ortho-C₃₋₅heterocyclylene, and ortho-C₅₋₆cycloalkylene, wherein R⁵ isoptionally substituted with one or more groups selected from C₁₋₆alkyl,halogenated C₁₋₆alkyl, —NO₂, —CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo,and iodo; and

D is selected from a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂—, —NH—,and —C(═O)—.

Particularly, the invention provides a process for preparing a compoundof formula I as described above, wherein

R¹ is C₁₋₆alkyl-O—C(═O)—;

R² and R³ are ethyl;

R⁴ is selected from phenyl-C₁₋₃alkyl, C₃₋₆cycloalkyl-C₁₋₃alkyl,C₃₋₆cycloalkyl, and phenyl, wherein R⁴ is optionally substituted withone or more groups selected from methyl, fluoro, chloro, bromo and iodo;

R⁵ is selected from ortho-phenylene, ortho-pyridylene,1,2-cyclopentylene, and 1,2-cyclohexylene; and

D is selected from a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂— and—C(═O)—.

More particularly, the compounds of the present invention andintermediates used for the preparation thereof can be prepared accordingto the synthetic routes as exemplified in Schemes 1-7.

Biological Evaluation

The compounds of the invention are found to be active towards δreceptors in warm-blooded animal, e.g., human. Particularly thecompounds of the invention are found to be effective δ receptor ligands.In vitro assays, infra, demonstrate these surprising activities,especially with regard to agonists potency and efficacy as demonstratedin the rat brain functional assay and/or the human δ receptor functionalassay (low). This feature may be related to in vivo activity and may notbe linearly correlated with binding affinity. In these in vitro assays,a compound is tested for their activity toward δ receptors and IC₅₀ isobtained to determine the selective activity for a particular compoundtowards δ receptors. In the current context, IC₅₀ generally refers tothe concentration of the compound at which 50% displacement of astandard radioactive δ receptor ligand has been observed.

The activities of the compound towards κ and μ receptors are alsomeasured in a similar assay.

In Vitro Model

Cell Culture

Human 293S cells expressing cloned human κ, δ and μ receptors andneomycin resistance are grown in suspension at 37° C. and 5% CO₂ inshaker flasks containing calcium-free DMEM 10% FBS, 5% BCS, 0.1%Pluronic F-68, and 600 μg/ml geneticin.

Rat brains are weighed and rinsed in ice-cold PBS (containing 2.5 mMEDTA, pH 7.4). The brains are homogenized with a polytron for 30 sec(rat) in ice-cold lysis buffer (50 mM Tris, pH 7.0, 2.5 mM EDTA, withphenylmethylsulfonyl fluoride added just prior use to 0.5 MmM from a0.5M stock in DMSO:ethanol).

Membrane Preparation

Cells are pelleted and resuspended in lysis buffer (50 mM Tris, pH 7.0,2.5 mM EDTA, with PMSF added just prior to use to 0.1 mM from a 0.1 Mstock in ethanol), incubated on ice for 15 min, then homogenized with apolytron for 30 sec. The suspension is spun at 1000 g (max) for 10 minat 4° C. The supernatant is saved on ice and the pellets resuspended andspun as before. The supernatants from both spins are combined and spunat 46,000 g (max) for 30 min. The pellets are resuspended in cold Trisbuffer (50 mM Tris/Cl, pH 7.0) and spun again. The final pellets areresuspended in membrane buffer (50 mM Tris, 0.32 M sucrose, pH 7.0).Aliquots (1 ml) in polypropylene tubes are frozen in dry ice/ethanol andstored at −70° C. until use. The protein concentrations are determinedby a modified Lowry assay with sodium dodecyl sulfate.

Binding Assays

Membranes are thawed at 37° C., cooled on ice, (or kept on ice if notused immediately) passed 3 times through a 25-gauge needle, and dilutedinto binding buffer (50 mM Tris, 3 mM MgCl₂, 1 mg/ml BSA (Sigma A-7888),pH 7.4, which is stored at 4° C. after filtration through a 0.22 mfilter, and to which has been freshly added 5 μg/ml aprotinin, 10 μMbestatin, 10 μM diprotin A if the membranes are derived from tissue(rat, mouse, monkey, no DTT). Aliquots of 100 μl are added to iced 12×75mm polypropylene tubes containing 100 μl of the appropriate radioligandand 100 μl of test compound at various concentrations. Total (TB) andnonspecific (NS) binding are determined in the absence and presence of10 μM naloxone respectively. The tubes are vortexed and incubated at 25°C. for 60-75 min, after which time the contents are rapidlyvacuum-filtered and washed with about 12 ml/tube iced wash buffer (50 mMTris, pH 7.0, 3 mM MgCl₂) through GF/B filters (Whatman) presoaked forat least 2 h in 0.1% polyethyleneimine. The radioactivity (dpm) retainedon the filters is measured with a beta counter after soaking the filtersfor at least 12 h in minivials containing 6-7 ml scintillation fluid. Ifthe assay is set up in 96-place deep well plates, the filtration is over96-place PEI-soaked unifilters, which are washed with 3×1 ml washbuffer, and dried in an oven at 55° C. for 2 h. The filter plates arecounted in a TopCount (Packard) after adding 50 μl MS-20 scintillationfluid/well. In the case of assays performed in 96 deep well plates, theIC50 of compounds are evaluated from 10-point displacement curves in thecase of Delta, and 5-point displacement curves in the case of Mu andKappa. The assay is done in 300 μl with the appropriate amount ofmembrane protein (2 μg, 35 μg, and 1 μg, in the case of Delta, Mu, andKappa, respectively) and 50000-80000 dpm/well of the appropriate tracer(125I-Deltorphin II, 125I-FK33824, and 125I-DPDYN for Delta, Mu, andKappa, respectively). The total binding and non-specific binding aredetermined in absence and presence of 10 μM of Naloxone.

Functional Assays

The agonist activity of the compounds is measured by determining thedegree to which the compounds receptor complex activates the binding ofGTP to G-proteins to which the receptors are coupled. In the GTP bindingassay, GTP[γ]³⁵S is combined with test compounds and membranes fromHEK-293S cells expressing the cloned human opioid receptors or fromhomogenised rat or mouse brain. Agonists stimulate GTP[γ]³⁵S binding inthese membranes. The EC₅₀ and E_(max) values of compounds are determinedfrom dose-response curves. Right shifts of the dose response curve bythe delta antagonist naltrindole are performed to verify that agonistactivity is mediated through delta receptors. For human δ receptorfunctional assays, EC₅₀ (low) is measured when the human δ receptorsused in the assay were expressed at lower levels in comparison withthose used in determining EC₅₀ (high). The E_(max) values weredetermined in relation to the standard δ agonist SNC80, i.e., higherthan 100% is a compound that have better efficacy than SNC80.

Procedure for Rat Brain GTP

Rat brain membranes are thawed at 37° C., passed 3 times through a25-gauge blunt-end needle and diluted in the GTPγS binding (50 mM Hepes,20 mM NaOH, 100 mM NaCl, 1 mM EDTA, 5 mM MgCl₂, pH 7.4, Add fresh: 1 mMDTT, 0.1% BSA). 120 μM GDP final is added membranes dilutions. The EC50and Emax of compounds are evaluated from 10-point dose-response curvesdone in 300 μl with the appropriate amount of membrane protein (20μg/well) and 100000-130000 dpm of GTPγ³⁵S per well (0.11-0.14 nM). Thebasal and maximal stimulated binding are determined in absence andpresence of 3 μM SNC-80. The assay performed on HEK 293s cells stablyexpressing cloned Delta receptors is done in a slightly different buffer(50 mM Hepes, 20 mM NaOH, 200 mM NaCl, 1 mM EDTA, 5 mM MgCl₂, pH 7.4,Add fresh: 0.5% BSA, no DTT) and with a 3 μM final conc. of GDP.

Data Analysis

The specific binding (SB) was calculated as TB-NS, and the SB in thepresence of various test compounds was expressed as percentage ofcontrol SB. Values of IC₅₀ and Hill coefficient (n_(H)) for ligands indisplacing specifically bound radioligand were calculated from logitplots or curve fitting programs such as Ligand, GraphPad Prism,SigmaPlot, or ReceptorFit. Values of K_(i) were calculated from theCheng-Prussoff equation. Mean±S.E.M. values of IC₅₀, K_(i) and n_(H)were reported for ligands tested in at least three displacement curves.

Measured using the above described assays, the IC₅₀ towards human δreceptor for most of the compounds of the present invention is generallyin the range of 0.32 nM-1.58 nM. The EC₅₀ and % E_(max) towards human δreceptor for these compounds are generally in the range of 5 nM-87 nMand 92-115, respectively. The IC₅₀ towards human κ and μ receptors forthese compounds is generally in the ranges of 450 nM-2509 nM and 87nM-1005 nM, respectively.

Receptor Saturation Experiments

Radioligand K_(δ) values are determined by performing the binding assayson cell membranes with the appropriate radioligands at concentrationsranging from 0.2 to 5 times the estimated K_(δ) (up to 10 times ifamounts of radioligand required are feasible). The specific radioligandbinding is expressed as pmole/mg membrane protein. Values of K_(δ) andB_(max) from individual experiments are obtained from nonlinear fits ofspecifically bound (B) vs. nM free (F) radioligand from individualaccording to a one-site model.

Determination of Mechano-Allodynia Using Von Frey Testing

Testing is performed between 08:00 and 16:00 h using the methoddescribed by Chaplan et al. (1994). Rats are placed in Plexiglas cageson top of a wire mesh bottom which allows access to the paw, and areleft to habituate for 10-15 min. The area tested is the mid-plantar lefthind paw, avoiding the less sensitive foot pads. The paw is touched witha series of 8 Von Frey hairs with logarithmically incremental stiffness(0.41, 0.69, 1.20, 2.04, 3.63, 5.50, 8.51, and 15.14 grams; Stoelting,Ill., USA). The von Frey hair is applied from underneath the mesh floorperpendicular to the plantar surface with sufficient force to cause aslight buckling against the paw, and held for approximately 6-8 seconds.A positive response is noted if the paw is sharply withdrawn. Flinchingimmediately upon removal of the hair is also considered a positiveresponse. Ambulation is considered an ambiguous response, and in suchcases the stimulus is repeated.

Testing Protocol

The animals are tested on postoperative day 1 for the FCA-treated group.The 50% withdrawal threshold is determined using the up-down method ofDixon (1980). Testing is started with the 2.04 g hair, in the middle ofthe series. Stimuli are always presented in a consecutive way, whetherascending or descending. In the absence of a paw withdrawal response tothe initially selected hair, a stronger stimulus is presented; in theevent of paw withdrawal, the next weaker stimulus is chosen. Optimalthreshold calculation by this method requires 6 responses in theimmediate vicinity of the 50% threshold, and counting of these 6responses begins when the first change in response occurs, e.g. thethreshold is first crossed. In cases where thresholds fall outside therange of stimuli, values of 15.14 (normal sensitivity) or 0.41(maximally allodynic) are respectively assigned. The resulting patternof positive and negative responses is tabulated using the convention,X=no withdrawal; O=withdrawal, and the 50% withdrawal threshold isinterpolated using the formula:50% g threshold=10^((Xf+kδ))/10,000where Xf=value of the last von Frey hair used (log units); k=tabularvalue (from Chaplan et al. (1994)) for the pattern of positive/negativeresponses; and δ=mean difference between stimuli (log units). Hereδ=0.224.

Von Frey thresholds are converted to percent of maximum possible effect(% MPE), according to Chaplan et al. 1994. The following equation isused to compute % MPE:${\%\quad{MPE}} = \frac{{{Drug}\quad{treated}\quad{threshold}\quad(g)} - {{allodynia}\quad{threshold}\quad(g) \times 100}}{{{Control}\quad{threshold}\quad(g)} - {{allodynia}\quad{threshold}\quad(g)}}$Administration oOf Test Substance

Rats are injected (subcutaneously, intraperitoneally, intravenously ororally) with a test substance prior to von Frey testing, the timebetween administration of test compound and the von Frey test variesdepending upon the nature of the test compound.

Writhing Test

Acetic acid will bring abdominal contractions when administeredintraperitoneally in mice. These will then extend their body in atypical pattern. When analgesic drugs are administered, this describedmovement is less frequently observed and the drug selected as apotential good candidate.

A complete and typical Writhing reflex is considered only when thefollowing elements are present: the animal is not in movement; the lowerback is slightly depressed; the plantar aspect of both paws isobservable. In this assay, compounds of the present inventiondemonstrate significant inhibition of writhing responses after oraldosing of 1-100 μmol/kg.

(i) Solutions Preparation

Acetic acid (AcOH): 120 μL of Acetic Acid is added to 19.88 ml ofdistilled water in order to obtain a final volume of 20 ml with a finalconcentration of 0.6% AcOH. The solution is then mixed (vortex) andready for injection.

Compound (drug): Each compound is prepared and dissolved in the mostsuitable vehicle according to standard procedures.

(ii) Solutions Administration

The compound (drug) is administered orally, intraperitoneally (i.p.),subcutaneously (s.c.) or intravenously (i.v.)) at 10 ml/kg (consideringthe average mice body weight) 20, 30 or 40 minutes (according to theclass of compound and its characteristics) prior to testing. When thecompound is delivered centrally: Intraventricularly (i.c.v.) orintrathecally (i.t.) a volume of 5 μL is administered.

The AcOH is administered intraperitoneally (i.p.) in two sites at 10ml/kg (considering the average mice body weight) immediately prior totesting.

(iii) Testing

The animal (mouse) is observed for a period of 20 minutes and the numberof occasions (Writhing reflex) noted and compiled at the end of theexperiment. Mice are kept in individual “shoe box” cages with contactbedding. A total of 4 mice are usually observed at the same time: onecontrol and three doses of drug.

For the anxiety and anxiety-like indications, efficacy has beenestablished in the geller-seifter conflict test in the rat.

For the functional gastrointestina disorder indication, efficacy can beestablished in the assay described by Coutinho S V et al, in AmericanJournal of Physiology—Gastrointestinal & Liver Physiology.282(2):G307-16, 2002 February in the rat.

Additional In Vivo Testrng Protocols

Subjects and Housing

Naïve male Sprague Dawley rats (175-200 g) are housed in groups of 5 ina temperature controlled room (22° C., 40-70% humidity, 12-hlight/dark). Experiments are performed during the light phase of thecycle. Animals have food and water ad libitum and are sacrificedimmediately after data acquisition.

Sample

Compound (Drug) testing includes groups of rats that do not receive anytreatment and others that are treated with E. coli lipopolysaccharide(LPS). For the LPS-treated experiment, four groups are injected withLPS, one of the four groups is then vehicle-treated whilst the otherthree groups are injected with the drug and its vehicle. A second set ofexperiments are conducted involving five groups of rats; all of whichreceive no LPS treatment. The naïve group receives no compound (drug) orvehicle; the other four groups are treated with vehicle with or withoutdrug. These are performed to determine anxiolytic or sedative effects ofdrugs which can contribute to a reduction in USV.

Administration of LPS

Rats are allowed to habituate in the experimental laboratory for 15-20min prior to treatment. Inflammation is induced by administration of LPS(endotoxin of gram-negative E. coli bacteria serotype 0111:B4, Sigma).LPS (2.4 μg) is injected intracerebro-ventricularly (i.c.v.), in avolume of 10 μl, using standard stereotaxic surgical techniques underisoflurane anaesthesia. The skin between the ears is pushed rostrallyand a longitudinal incision of about 1 cm is made to expose the skullsurface. The puncture site is determined by the coordinates: 0.8 mmposterior to the bregma, 1.5 mm lateral (left) to the lambda (sagittalsuture), and 5 mm below the surface of the skull (vertical) in thelateral ventricle. LPS is injected via a sterile stainless steel needle(26-G ⅜) of 5 mm long attached to a 100-μl Hamilton syringe bypolyethylene tubing (PE20; 10-15 cm). A 4 mm stopper made from a cutneedle (20-G) is placed over and secured to the 26-G needle by siliconeglue to create the desired 5 mm depth.

Following the injection of LPS, the needle remains in place for anadditional 10 s to allow diffusion of the compound, then is removed. Theincision is closed, and the rat is returned to its original cage andallowed to rest for a minimum of 3.5 h prior to testing.

Experimental Setup for Air-Puff Stimulation

The rats remains in the experimental laboratory following LPS injectionand compound (drug) administration. At the time of testing all rats areremoved and placed outside the laboratory. One rat at a time is broughtinto the testing laboratory and placed in a clear box (9×9×18 cm) whichis then placed in a sound-attenuating ventilated cubicle measuring62(w)×35(d)×46(h) cm (BRS/LVE, Div. Tech-Serv Inc). The delivery ofair-puffs, through an air output nozzle of 0.32 cm, is controlled by asystem (AirStim, San Diego Intruments) capable of delivering puffs ofair of fixed duration (0.2 s) and fixed intensity with a frequency of 1puff per 10 s. A maximun of 10 puffs are administered, or untilvocalisation starts, which ever comes first. The first air puff marksthe start of recording.

Experimental Setup for and Ultrasound Recording

The vocalisations are recorded for 10 minutes using microphones(G.R.A.S. sound and vibrations, Vedbaek, Denmark) placed inside eachcubicle and controlled by LMS (LMS CADA-X 3.5B, Data AcquisitionMonitor, Troy, Mich.) software. The frequencies between 0 and 32000 Hzare recorded, saved and analysed by the same software (LMS CADA-X 3.5B,Time Data Processing Monitor and UPA (User Programming and Analysis)).

Compounds (Drugs)

All compounds (drugs) are pH-adjusted between 6.5 and 7.5 andadministered at a volume of 4 ml/kg. Following compound (drug)administration, animals are returned to their original cages until timeof testing.

Analysis

The recording is run through a series of statistical and Fourieranalyses to filter (between 20-24 kHz) and to calculate the parametersof interest. The data are expressed as the mean±SEM. Statisticalsignificance is assessed using T-test for comparison between naive andLPS-treated rats, and one way ANOVA followed by Dunnett's multiplecomparison test (post-hoc) for drug effectiveness. A difference betweengroups is considered significant with a minimum p value of ≦0.05.Experiments are repeated a minimum of two times.

Determination of Thermal Hvperalgesia Using the Hargreaves Plantar Test

Administration of FCA or Carrageenan

Freund's Complete Adjuvant (FCA): SIGMA cat.# F 5881, Mycabacteriumtuberculosis (H37Ra, ATCC 25177), 1 mg/ml, heat killed, dried, 0.85 mlparaffin, 0.15 ml mannide monooleate. Or carrageenan Lambda type IV(Cg):SIGMA cat.# C-3889, (Gelatin, vegetable; Irish moss), (1.0% solution) inNaCl.

Injections are done with a Hamilton syringe with a sterile needle size26G⅝″. Rats are handled and placed in chamber for anaesthesia withisoflurane. When the desired effect is reached, the rat is removed andplaced on ventral decubitus (sternal position). The left hind paw isgrasped and the needle is introduced subcutaneous, ventral aspect,between footpad of finger # 2 and # 3 in order the reach the middle ofthe paw (metatarsal area). Finally, a volume of 100 μl FCA, or 100 μl ofcarrageenan solution, is slowly injected into the paw, and a smallpressure is applied for 3-4 seconds after removal of needles.

If the animals are waking up during the procedure, they are then returnin the inhalation chamber until desired effect is reached.

After the intraplantar injection, the animals are allowed to wake upunder observation in their cage.

For FCA treatment, rats are allowed 48 hours for the development of theinflammatory process. For carrageenan treatment, rats are allowed 3hours for the development of the inflammatory process. On the morning ofthe test, rats are placed in the lab (in their cages). They are allowedto habituate to the room for at least 30 minutes.

Test Site

The heat stimulus is applied to the center of the plantar surface, inbetween the pads. The test site must be in contact with the glass, withno urine or feces in between, in order to maintain the correct heattransfer properties from the glass to the skin.

The plantar apparatus consists of a box with a glass top/platform, theglass surface is maintained at 30° C. by an internal feedback mechanism.Underneath this glass platform is a light bulb mounted on a moveablearm, a mirror is placed underneath to allow the light to be positionedunder the rat's paw. When the light is activated it shines through anaperture of ˜2 mm diameter. The experimenter activates the light, andautomatic sensors turn the light off when the paw is removed; a cut-offof 20.48 seconds ensures that no tissue damage will occur should the ratfail to remove his paw. The experimenter may also turn off the light atany point. A Timer will record the duration of time that the light isactivated.

Flux meter: measures the flux/cm2 when the light is activated. Thisshould be maintained at ˜97-98; the flux can be modified by adjustingthe plantar device, but must never be changed in the middle of anexperiment.

Time-Course

The experiment can be performed after varying lengths of time followingthe induction of inflammation. Hyperalgesia is measured at 48 h post-FCAinjection or 3 h post-carrageenan injection.

Test Procedure

Naïve rats: For the procedure of establishing a Dose Response Curve, onegroup of 7 rats is used as a control group; they are anesthetised withthe remaining 28 rats, but are not given any injection. Testing of thenaive group may be done either prior to beginning or immediatelyfollowing the experiment, with the minimum stress possible, the rats areplaced in individual Plexiglas boxes (14×21×9 cm) on top of the plantardevice; they are allowed to habituate for a period of 30 minutes. Whenthe animals are ready to test, the light is placed directly under thetest-site and activated, and the latency to withdrawal is recorded.After a period of 5-8 minutes, to allow skin temperature to return tonormal, a second reading is taken, and the rats are then removed andreplaced in their cage.

Baseline Values: The remaining 28 rats (divided into 4 groups) that havebeen injected with FCA (or carrageenan) are placed in individual boxeson the machine and allowed to habituate for 30 minutes. The experimentershould verify the degree of inflammation of the paw and check fordiscoloration. The heat stimulus is placed under the test site, and thelatency to withdrawal is recorded; two readings are taken, as above. Itis the comparison of these baseline values with those of the naïveanimals that establishes whether hyperalgesia is present.

Post-drug testing: Once hyperalgesia is established, the rats areinjected with the compound of interest. Each compound is prepared anddissolved in the most suitable vehicle according to standard procedures.The administration route, doses, volume, and time of testing afterinjection is specific for that compound (or class of compounds). Whentesting compounds at 20-30 minutes post-injection, such as for i.v. ors.c. injections, rats are placed and allowed to habituate on the plantarapparatus while the drug produces its effect. When testing compounds at60 minutes or more following the injection, rats are placed back intheir original cage with their cage mates. Rats are always replaced intheir original cages with their original cage mates to minimize thestress of re-establishing a social structure within a group of rats. 30min later rats are placed one the plantar and allowed 30 minutes tohabituate to the plantar machine. Testing is performed as describedabove. Two readings are taken

Criteria for Testing:

The animal must be calm and quiet, yet alert, and in the correctposition, with no urine or feces between the skin of the paw and theglass surface of the machine. An animal should not be tested if:

-   -   The animal is in locomotion, including sniffing, grooming and        exploring.    -   The animal is sleeping.    -   The animal is showing obvious signs of stress (tonic immobility,        vocalizations, ears flat), unless these are the possible result        of a compound side effect and cannot be avoided.    -   The animal is positioned in such a way that the paw is not in        direct contact with the glass (paw resting on top of tail);    -   The animal's paw is displaying blue coloring as a result of a        bad injection. In this case, the animal is rejected from the        experiment completely (at the beginning).

When urine or feces are present, the animal is removed, the glasssurface is wiped clean, and then the animal is replaced. When the animalis sleeping, or exhibiting tonic immobility, the experimenter may gentlymove the box or move their hand in front of the box to elicit ashort-term attentional behaviour. Close observation of the animal'sbehaviour should be conducted throughout the test.

Re-Tests:

At any time during the experiment, if the experimenter is not certainthat the paw withdrawal response was not a response to the heatstimulus, the animal may be re-tested after 5-8 minutes. This may be dueto the animal moving suddenly, or urinating or defecating while thestimulus is being applied.

Acceptable Responses:

any of the following are considered responses to the heat stimulus

-   -   Withdrawal movement of the paw off the glass (often followed by        paw licking)    -   Lateral movement of the body (contralateral for the stimulated        paw)    -   Toes are moving off the glass    -   the centroplanar (middle paw) aspect of the inflamed paw is        removed from the glass.        Analysis

The data are expressed as the mean±SEM. Statistical significance isassessed using T-test for comparison between naive and inflamed rats,and one way ANOVA followed by Dunnett's multiple comparison test(post-hoc) for drug effectiveness. A difference between groups isconsidered significant with a minimum p value of ≦0.05.

EXAMPLES

The invention will further be described in more detail by the followingExamples which describe methods whereby compounds of the presentinvention may be prepared, purified, analyzed and biologically tested,and which are not to be construed as limiting the invention.

Intermediate 1

A mixture of 4-(bromomethyl)benzoic acid, methyl ester (11.2 g, 49 mmol)and trimethyl phosphite (25 mL) was refluxed under N₂ for 5 hrs. Excesstrimethyl phosphite was removed by co-distillation with toluene to giveINTERMEDIATE 1 in quantitative yield. ¹H NMR (CDCl₃) δ 3.20 (d, 2H, J=22Hz, CH₂), 3.68 (d, 3H 10.8 Hz, OCH₃), 3.78 (d, 3H, 11.2 Hz, OCH₃), 3.91(s, 3H, OCH₃), 7.38 (m, 2H, Ar—H), 8.00 (d, 2H, J=8 Hz, Ar—H).

Intermediate 2:4-(4-Methoxycarbonyl-benzylidene)-piperidine-1-carboxylic acidtert-butyl ester

To a solution of INTERMEDIATE 1 in dry THF (200 mL) was added dropwiselithium diisopropylamide (32.7 mL 1.5 M in hexanes, 49 mmol) at −78° C.The reaction mixture was then allowed to warm to room temperature priorto addition of N-tert-butoxycarbonyl-4-piperidone (9.76 g, 49 mmol in100 mL dry THF). After 12 hrs, the reaction mixture was quenched withwater (300 mL) and extracted with ethyl acetate (3×300 mL). The combinedorganic phases were dried over MgSO₄ and evaporated to give a crudeproduct, which was purified by flash chromatography to provideINTERMEDIATE 2 as a white solid (5.64 g, 35%). IR (NaCl) 3424, 2974,2855, 1718, 1688, 1606, 1427, 1362, 1276 cm⁻¹; ¹H NMR (CDCl₃) δ 1.44 (s,9H), 2.31 (t, J=5.5 Hz, 2H), 2.42 (t, J=5.5 Hz, 2H), 3.37 (t, J=5.5 Hz,2H), 3.48 (t, J=5.5 Hz, 2H), 3.87 (s, 3H, OCH₃), 6.33 (s, 1H, CH), 7.20(d J=6.7 Hz, 2H, Ar—H), 7.94 (d, J,=6.7 Hz, 2H, Ar—H); ¹³C NMR (CDCl₃) δ28.3, 29.2, 36.19, 51.9, 123.7, 127.8, 128.7, 129.4, 140.5, 142.1,154.6, 166.8.

Intermediate 3:4-Bromo-4-[bromo-(4-methoxycarbonyl-phenyl)-methyl]-piperidine-1-carboxylicacid tert-butyl ester

To a mixture of INTERMEDIATE 2 (5.2 g, 16 mmol) and K₂CO₃ (1.0 g) in drydichloromethane (200 mL) was added a solution of bromine (2.9 g, 18mmol) in 30 mL CH₂Cl₂ at 0° C. after 1.5 hrs at room temperature, thesolution after filtration of K₂CO₃ was condensed. The residue was thendissolved in ethyl acetate (200 mL), washed with water (200 mL), 0.5 MHCl (200 mL) and brine (200 mL), and dried over MgSO₄. Removal ofsolvents provided a crude product, which was recrystallized frommethanol to give INTERMEDIATE 3 as a white solid (6.07 g, 78%). IR(NaCl) 3425, 2969, 1725, 1669, 1426, 1365, 1279, 1243 cm⁻¹; ¹H NMR(CDCl₃) δ 1.28 (s, 9H), 1.75 (m, 1H), 1.90 (m, 1H), 2.1 (m, 2H), 3.08(br, 2H), 3.90 (s, 3H, OCH₃), 4.08 (br, 3H), 7.57 (d, J=8.4 Hz, 2H,Ar—H) 7.98 (d, J=8.4 Hz, 2H, Ar—H); ¹³C NMR (CDCl₃) δ 28.3, 36.6, 38.3,40.3, 52.1, 63.2, 72.9, 129.0, 130.3, 130.4, 141.9, 154.4, 166.3.

Intermediate 4:4-[Bromo-(4-carboxy-phenyl)-methylene]-piperidine-1-carboxylic acidtert-butyl ester

A solution of INTERMEDIATE 3 (5.4 g 11 mmol) in methanol (300 mL) and2.0 M NaOH (100 mL) was heated at 40° C. for 3 hrs. The solid wascollected by filtration, and dried overnight under vacuum. The dry saltwas dissolved in 40% acetonitrile/water, and was adjusted to pH 2 usingconcentrated HCl. INTERMEDIATE 4 (3.8 g, 87%) was isolated as a whitepowder by filtration. ¹H NMR (CDCl₃) δ 1.45 (s, 9H, ^(t)Bu), 2.22 (dd,J=5.5 Hz, 6.1 Hz, 2H), 2.64 (dd, J=5.5 Hz, 6.1 Hz, 2H), 3.34 (dd, J=5.5Hz, 6.1 Hz, 2H), 3.54 (dd, J=5.5 Hz, 6.1 Hz, 2H), 7.35 (d, J=6.7 Hz, 2H,Ar—H), 8.08 (d, J=6.7 Hz, 2H, Ar—H); ¹³C NMR (CDCl₃) δ 28.3, 31.5, 34.2,44.0, 115.3, 128.7, 129.4, 130.2, 137.7, 145.2, 154.6, 170.3.

Intermediate 5:4-[Bromo-(4-diethylcarbamoyl-phenyl)-methylene]-piperidine-1-carboxylicacid tert-butyl ester

To a solution of INTERMEDIATE 4 (1.0 g, 2.5 mmol) in dry dichloromethane(10 mL) at −20° C. was added isobutylchloroformate (450 mg, 3.3 mmol).After 20 min at −20° C. diethylamine (4 mL) was added and the reactionwas allowed to warm to room temperature. After 1.5 hrs the solvents wereevaporated and the residue was partitioned between ethyl acetate andwater. The organic phase was washed with brine and dried over MgSO₄.Removal of solvents provided a crude product, which was purified byflash chromatography to give INTERMEDIATE 5 as white needles (800 mg,73%). IR (NaCl) 3051, 2975, 1694, 1633, 1416, 1281, 1168, 1115 cm⁻¹; ¹HNMR (CDCl₃) δ 1.13 (br, 3H, CH₃), 1.22 (br, 3H, CH₃), 1.44 (s, 9H,^(t)Bu), 2.22 (t, J=5.5 Hz, 2H), 2.62 (t, J=5.5 Hz, 2H), 3.33 (m, 4H),3.55 (m, 4H), 7.31 (d, J=8.0 Hz, 2H, Ar—H), 7.36 (d, J=8.0 Hz, 2H,Ar—H); ¹³C NMR (CDCl₃) δ 12.71, 14.13, 28.3, 31.5, 34.2, 39.1, 43.2,79.7, 115.9, 126.3, 129.3, 136.8, 137.1, 140.6, 154.6, 170.5.

Intermediate 6:4-[[4-[(Diethylamino)carbonyl]phenyl](2-hydroxyphenyl)methylene]-1-piperidinecarboxylicacid, tert-butyl ester

To a mixture of INTERMEDIATE 5 (1.01 g, 2.23 mmol),(2-hydroxyphenyl)boronic acid (0.461 g, 3.34 mmol), toluene (18 mL),ethanol (4.2 mL), and 2.0 M Na₂CO₃ (2.8 mL) in a N₂ purged roundbottomed flask was added palladium tetrakistriphenylphosphine (0.258 g,0.223 mmol). The resulting mixture was heated overnight at 90° C. underN₂. The reaction was then concentrated in vacuo and the residue wasdiluted with water (20 mL) and CH₂Cl₂ (20 mL). The layers wereseparated, and the aqueous phase was extracted with CH₂Cl₂. The combinedorganic phases were dried over Na₂SO₄, filtered, and concentrated invacuo. The crude product was purified by silica gel columnchromatography eluting with 2:1 CH₂Cl₂:EtOAc to give INTERMEDIATE 6 as abrown solid (1.05 g, quantitative yield). ¹H NMR (400 MHz, CDCl₃) δ 1.10(br s, 3H), 1.22 (br s, 3H), 1.45 (s, 9H), 2.19 (t, J=5.8 Hz, 2H), 2.41(br s, 2H), 3.19-3.59 (br m, 8H), 5.49 (br s, 1H), 6.85 (td, J=1.2 Hz,7.4 Hz, 1H), 6.89 (dd, J=1.0 Hz, 8.2 Hz, 1H), 6.95 (dd, J=1.6 Hz, 7.6Hz, 1H), 7.13-7.18 (m, 3H), 7.28-7.31 (m, 2H).

Compound 1:N,N-Diethyl-4-[(2-phenoxyphenyl)-4-piperidinylidenemethyl]-benzamide

To a mixture of INTERMEDIATE 5 (0.200 g, 0.443 mmol),(2-phenoxyphenyl)boronic acid (0.142 g, 0.664 mmol), toluene (3.6 mL),ethanol (0.84 mL), and 2.0 M Na₂CO₃ (0.56 mL) in a N₂ purged microwaveprocess vial was added palladium tetrakistriphenylphosphine (0.0511 g,0.044 mmol). The resulting mixture was subjected to microwaveirradiation and heated to 120° C. for 40 min. The reaction was thenconcentrated in vacuo and the residue was diluted with water (4 mL) andCH₂Cl₂ (4 mL). The layers were separated, and the aqueous phase wasextracted with CH₂Cl₂. The combined organic phases were dried overNa₂SO₄, filtered, and concentrated in vacuo. The crude product waspurified by silica gel column chromatography eluting with 2:1toluene:EtOAc. The purified product was dissolved in CH₂Cl₂ (10 mL) andtrifluoroacetic acid (1 mL) was added. After 2 h, the reaction wasconcentrated in vacuo. The residue was lyophilized from CH₃CN/H₂O togive COMPOUND I as its trifluoroacetic acid salt (0.196 g, 68%) as aslightly yellow solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ1.08 (br t, J=6.7 Hz, 3H), 1.22 (br t, J=6.8 Hz, 3H), 2.41-2.66 (m, 4H),2.96-3.13 (m, 2H), 3.14-3.27 (m, 4H), 3.45-3.58 (m, 2H), 6.71-6.77 (m,2H), 6.90 (dd, J=1.1 Hz, 8.1 Hz, 1H), 7.00-7.06 (m, 1H), 7.16-7.36 (m,9H). Found: C, 61.32; H, 5.41; N, 4.45. C₂₉H₃₂N₂O₂×1.7 CF₃CO₂H has C,61.34; H, 5.35; N, 4.42%.

Compound 2:4-[[2-(Benzyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethyl-benzamide

Using the same method as for COMPOUND I and using INTERMEDIATE 5 (0.200g, 0.443 mmol) and (2-benzyloxy)phenylboronic acid (0.152 g, 0.665 mmol)afforded COMPOUND 2 as its trifluoroacetic acid salt (0.194 g, 65%) as aslightly yellow solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ1.10 (br t, J=6.5 Hz, 3H), 1.23 (br t, J=6.9 Hz, 3H), 2.34-2.46 (m, 2H),2.51-2.67 (m, 2H), 2.97-3.09 (m, 2H), 3.12-3.23 (m, 2H), 3.23-3.34 (m,2H), 3.53 (br q, J=6.9 Hz, 2H), 4.99 (half of AB_(q), 1H), 5.07 (half ofAB_(q), 1H), 6.96 (td, J=1.0 Hz, 7.4 Hz, 1H), 7.08 (d, J=8.4 Hz, 1H),7.12 (dd, J=1.7 Hz, 7.5 Hz, 1H), 7.22-7.38 (m, 10H). Found: C, 62.39; H,5.71; N, 4.34. C₃₀H₃₄N₂O₂×1.6 CF₃CO₂H×0.1 H₂O has C, 62.42; H, 5.65; N,4.38%.

Compound 3:N,N-Diethyl-4-(4-phenoxathiinyl-4-piperidinylidenemethyl)-benzamide

To a mixture of INTERMEDIATE 5 (0.202 g, 0.448 mmol), 4-phenoxathiinylboronic acid (0.164 g, 0.672 mmol), toluene (3.6 mL), ethanol (0.84 mL),and 2.0 M Na₂CO₃ (0.56 mL) in a N₂ purged vial was added palladiumtetrakistriphenylphosphine (0.0518 g, 0.045 mmol). The resulting mixturewas heated at 90° C. for 24 h. The reaction was then concentrated invacuo and the residue was diluted with water (4 mL) and CH₂Cl₂ (4 mL).The layers were separated, and the aqueous phase was extracted withCH₂Cl₂. The combined organic phases were dried over Na₂SO₄, filtered,and concentrated in vacuo. The crude product was purified by silica gelcolumn chromatography eluting with 5:1 CH₂Cl₂:EtOAc. The purifiedproduct was dissolved in CH₂Cl₂ (10 mL) and trifluoroacetic acid (1 mL)was added. After 1.5 h, the reaction was concentrated in vacuo. Theresidue was lyophilized from CH₃CN/H₂O to give COMPOUND 3 as itstrifluoroacetic acid salt (0.250 g, 95%) as a slightly yellow solid.Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.06 (br t, J=6.9 Hz,3H), 1.22 (br t, J=7.2 Hz, 3H), 2.44-2.58 (m, 2H), 2.63-2.73 (m, 1H),2.74-2.83 (m, 1H), 3.18-3.28 (m, 5H), 3.31-3.40 (m, 1H), 3.52 (br q,J=7.4 Hz, 2H), 6.75 (dd, J=1.3 Hz, 7.9 Hz, 1H), 6.98-7.13 (m, 5H),7.14-7.17 (m, 1H), 7.35 (s, 4H).

Compound 4:4-(4-Dibenzofuranyl-4-piperidinylidenemethyl)-N,N-diethylbenzamide

Using the same method as for COMPOUND 3 and using INTERMEDIATE 5 (0.201g, 0.445 mmol) and 4-dibenzofuranylboronic acid (0.142 g, 0.667 mmol)afforded COMPOUND 4 as its trifluoroacetic acid salt (0.238 g, 97%) as aslightly yellow solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ1.09 (br t, J=6.8 Hz, 3H), 1.22 (br t, J=6.8 Hz, 3H), 2.49 (br t, J=6.0Hz, 2H), 2.74 (br t, J=6.1 Hz, 2H), 3.23-3.37 (m, 6H), 3.47-3.56 (m,2H), 7.23 (dd, J=1.2 Hz, 7.4 Hz, 1H), 7.33-7.41(m, 6H), 7.49 (td, J=1.2Hz, 7.8 Hz, 1H), 7.54-7.58 (m, 1H), 7.99 (dd, J=1.3 Hz, 7.7 Hz, 1H),8.04 (dd, J=0.6 Hz, 7.6 Hz, 1H).

Compound 5:4-[[2-(Cyclopentyloxy)phenyl]-4-piperidinylidenemethyl]-N,N-diethylbenzamide

To a mixture of INTERMEDIATE 6 (0.223 g, 0.480 mmol), bromocyclopentane(0.077 mL, 0.72 mmol), and Cs₂CO₃ (0.626 g, 1.92 mmol) in DMF (5.5 mL)was added NaI (0.040 g, 0.27 mmol). The resulting mixture was stirred atroom temperature for 15 h. The reaction was then diluted with CH₂Cl₂ (50mL) and washed with water and brine. The organic phase was dried overNa₂SO₄, filtered, and concentrated in vacuo. The crude product waspurified by silica gel column chromatography eluting with 5:1CH₂Cl₂:EtOAc. The purified product was dissolved in CH₂Cl₂ (10 mL) andtrifluoroacetic acid (1 mL) was added. After 1.5 h, the reaction wasconcentrated in vacuo. The residue was lyophilized from CH₃CN/H₂O togive COMPOUND 5 as its trifluoroacetic acid salt (0.248 g, 94%) as aslightly yellow solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ1.11 (br t, J=6.5 Hz, 3H), 1.23 (br t, J=7.1 Hz, 3H), 1.39-1.83 (m, 7H),1.88-2.00 (m, 1H), 2.33-2.50 (m, 2H), 2.55-2.69 (m, 2H), 3.16-3.24 (m,4H), 3.25-3.31 (m, 2H), 3.47-3.58 (m, 2H), 4.75-4.81 (m, 1H), 6.91 (td,J=1.0 Hz, 7.4 Hz, 1H), 6.95 (d, J=8.6 Hz, 1H), 7.13 (dd, J=1.7 Hz, 7.5Hz, 1H), 7.22-7.28 (m, 3H), 7.28-7.33 (m, 2H).

Intermediate 7: tert-butyl4-[{4-[(diethylamino)carbonyl]phenyl}(3-hydroxyphenyl)methylene]piperidine-1-carboxylate

To a flask containing INTERMEDIATE 5 (4.08 g, 9.04 mmol) was addedtoluene (100 mL), ethanol (100 mL), 3-hydroxyphenylboronic acid (1.97 g,14.3 mmol), and aqueous 2N sodium carbonate (11.3 mL, 22.6 mmol). Thesolution was degassed for 20 minutes, then palladiumtetrakistriphenylphosphine (1.05 g, 0.909 mmol) was added. The reactionmixture was purged with nitrogen and heated to 90° C. After 5 h, thereaction was cooled to rt and saturated aqueous ammonium chloride wasadded. The mixture was extracted with two portions of ethyl acetate andthe combined organic extracts were dried (Na₂SO₄), filtered andconcentrated. The residue was purified by flash chromatography, eluting0% to 100% ethyl acetate in hexanes, to yield INTERMEDIATE 7 as acolourless solid (4.24 g, 100%). ¹H NMR (400 MHz, CDCl₃) δ 1.10 (t,J=7.42 Hz, 3H), 1.20 (t, J=7.03 Hz, 3H), 1.42 (s, 9H), 2.25-2.33 (m,4H), 3.23-3.31 (m, 2H), 3.39-3.46 (m, 4H), 3.46-3.54 (m, 2H), 6.51 (dd,J=2.15, 1.56 Hz, 1H), 6.57 (ddd, J=7.62, 1.56, 0.98 Hz, 1H), 6.62 (ddd,J=8.20, 2.54, 0.98 Hz, 1H), 7.06-7.12 (m, 1H), 7.19 (d, J=8.40 Hz, 2H),7.29 (d, J=8.40 Hz, 2H).

Compound 6:4-[[3-(benzyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide

To a solution of INTERMEDIATE 7 (0.100 g, 0.215 mmol) in dry DMF wasadded benzyl bromide (50 μL, 0.42 mmol) and potassium carbonate (0.150g, 1.09 mmol). The reaction was heated to 80° C. and stirred for 24 h.After cooling to room temperature, the reaction mixture was diluted withethyl acetate and washed with two portions of 1M HCl then brine. Theorganic layer was dried (Na₂SO₄), filtered and concentrated. The residuewas dissolved in CH₂Cl₂ and trifluoroacetic acid (1 mL) was added. After2 h, the reaction was concentrated and the residue purified by reversephase chromatography, eluting 10% to 45% acetonitrile in watercontaining 0.1% trifluoroacetic acid. The product was obtained as thetrifluoroacetic acid salt and was lyophilized to give COMPOUND 6 (62 mg,51%) as a colourless solid. Purity (HPLC): >99% (215 nm), >99% (254nm), >99% (280 nm); ¹H NMR (400 MHz, CD₃OD) δ 1.12 (br t, J=7.03 Hz,3H), 1.24 (br t, J=7.03 Hz, 3H), 2.49-2.60 (m, 4H), 3.15-3.21 (m, 2H),3.20-3.26 (m, 2H), 3.25-3.35 (m, 2H), 3.48-3.59 (m, 2H), 5.06 (s, 2H),6.70-6.77 (m, 2H), 6.90-6.96 (m, 1H), 7.24 (d, J=8.40 Hz, 2H), 7.26-7.41(m, 8H).

Compound 7:N,N-diethyl-4-[[3-(2-phenylethoxy)phenyl](piperidin-4-ylidene)methyl]benzamide

Using the procedure described for COMPOUND 6 with INTERMEDIATE 7 (0.146g, 0.314 mmol) and 2-bromoethylbenzene (86 μL, 0.63 mmol) providedCOMPOUND 7 (60 mg, 36%) as a colourless solid. Purity (HPLC): >99% (215nm), >99% (254 nm), >99% (280 nm); ¹H NMR (400 MHz, CD₃OD) δ 1.10 (br t,J=6.83 Hz, 3H), 1.23 (br t, J=6.83 Hz, 3H), 2.54-2.60 (m, 4H), 3.02 (t,J=6.83 Hz, 2H), 3.20-3.33 (m, 6H), 3.48-3.58 (m, 2H), 4.13 (t, J=6.93Hz, 2H), 6.65 (dd, J=2.34, 1.56 Hz, 1H), 6.74 (ddd, J=7.62, 1.56, 0.98Hz, 1H), 6.84 (ddd, J=8.20, 2.54, 0.59 Hz, 1H), 7.16-7.30 (m, 8H), 7.35(d, J=8.40 Hz, 2H).

Compound 8:4-[[3-(cyclopentyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide

Using the procedure described for COMPOUND 6 with INTERMEDIATE 7 (0.200g, 0.430 mmol) and cyclopentyl bromide (92 μL, 0.86 mmol) providedCOMPOUND 8 (78 mg, 33%) as a colourless solid. Purity (HPLC): >99% (215nm), >99% (254 nm), >99% (280 nm); ¹H NMR (400 MHz, CD₃OD) δ 1.12 (br t,J=7.23 Hz, 3H), 1.23 (br t, J=7.23 Hz, 3H), 1.53-1.67 (m, 2H), 1.68-1.81(m, 4H), 1.80-1.95 (m, 2H), 2.54-2.63 (m, 4H), 3.21-3.35 (m, 6H),3.48-3.58 (m, 2H), 4.71-4.78 (m, 1H), 6.62 (dd, J=2.34, 1.76 Hz, 1H),6.71 (ddd, J=7.42, 1.37, 0.98 Hz, 1H), 6.80 (ddd, J=8.40, 2.34, 0.78 Hz,1H), 7.19-7.29 (m, 3H), 7.36 (d, J=8.40 Hz, 2H). Found: C, 62.54; H,6.54; N, 4.73. C₂₈H₃₆N₂O₂×1.3 CF₃CO₂H×0.4 H₂O has C, 62.50; H, 6.53; N,4.76%.

Compound 9:4-[[3-(cyclohexyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide

Using the procedure described for COMPOUND 6 with INTERMEDIATE 7 (0.332g, 0.715 mmol) and cyclohexyl bromide (0.10 mL, 0.81 mmol) providedCOMPOUND 9 (168 mg, 42%) as a colourless solid. Purity (HPLC): >96% (215nm), >99% (254 nm), >99% (280 nm); ¹H NMR (400 MHz, CD₃OD) δ 1.12 (t,J=6.83 Hz, 3H), 1.23 (t, J=6.83 Hz, 3H), 1.28-1.52 (m, 5H), 1.52-1.61(m, 1H), 1.71-1.81 (m, 2H), 1.87-1.96 (m, 2H), 2.55-2.63 (m, 4H),3.21-3.34 (m, 6H), 3.49-3.58 (m, 2H), 4.21-4.31 (m, 1H), 6.65 (dd,J=2.34, 1.76 Hz, 1H), 6.72 (ddd, J=7.62, 1.37, 0.98 Hz, 1H), 6.83 (ddd,J=8.40, 2.54, 0.78 Hz, 1H), 7.20-7.29 (m, 3H), 7.36 (d, J=8.40 Hz, 2H).

Intermediate 8: tert-butyl4-[{4-[(diethylamino)carbonyl]phenyl}(3-{[(trifluoromethyl)sulfonyl]oxy}phenyl)methylene]piperidine-1-carboxylate

To a solution of INTERMEDIATE 7 (1.95 g, 4.20 mmol) and triethylamine(3.00 mL, 21.5 mmol) in dichloromethane (15 mL) was addedtrifluoromethanesulfonic anhydride (0.95 mL, 5.65 mmol) dropwise at 0°C. The reaction was allowed to warm to room temperature and was stirredfor 15 hours. The solution was diluted with dichloromethane and waswashed with two portions of saturated aqueous ammonium chloride, thendried (Na₂SO₄), filtered and concentrated. The residue was purified byflash chromatography, eluting 20% to 50% ethyl acetate in hexanes toyield INTERMEDIATE 8 (2.00 g, 80%) as a yellow foam. ¹H NMR (400 MHz,CDCl₃) δ 1.08-1.18 (m, 3H), 1.20-1.29 (m, 3H), 1.47 (s, 9H), 2.29-2.38(m, 4H), 3.23-3.34 (m, 2H), 3.44-3.50 (m, 4H), 3.50-3.60 (m, 2H),7.02-7.05 (m, 1H), 7.09-7.18 (m, 4H), 7.34 (d, J=8.01 Hz, 2H), 7.36-7.41(m, 1H).

Compound 10:N,N-diethyl-4-[(3-phenoxyphenyl)(piperidin-4-ylidene)methyl]benzamide

An oven-dried 2-necked round bottom flask equipped with a refluxcondenser was charged with Pd₂(dba)₃ (7.5 mg, 0.008 mmol),2-(di-t-butylphosphino)biphenyl (5.5 mg, 0.018 mmol), K₃PO₄ (77 mg, 0.36mmol), and phenol (19 mg, 0.20 mmol). The flask was fitted with a rubberseptum, purged with nitrogen, and then a solution of INTERMEDIATE 8 (100mg, 0.168 mmol) in degassed toluene (2 mL) was added through the septum.The reaction was heated to 80° C. and stirred for 22 h. The flask wascooled to room temperature and the mixture was absorbed onto silica gel.Flash chromatography, eluting 20% to 50% ethyl acetate in hexanesafforded the BOC-protected derivative (50 mg, 0.093 mmol) as a yellowoil. The oil was dissolved in dichloromethane (5 mL) and trifluoroaceticacid (0.5 mL) was added. After 4 h, the solution was concentrated andpurified by reverse phase chromatography, eluting 10% to 45%acetonitrile in water containing 0.1% trifluoroacetic acid. The productwas obtained as the trifluoroacetic acid salt and was lyophilized togive COMPOUND 10 (44 mg, 47%) as a white solid. Purity (HPLC): >99% (215nm), >99% (254 nm), >99% (280 nm); ¹H NMR (400 MHz, CD₃OD) δ 1.12 (br t,J=7.03 Hz, 3H), 1.23 (br t, J=6.83 Hz, 3H), 2.54-2.63 (m, 4H), 3.20-3.26(m, 4H), 3.26-3.34 (m, 2H), 3.49-3.58 (m, 2H), 6.75-6.78 (m, 1H),6.86-6.99 (m, 4H), 7.07-7.14 (m, 1H), 7.25 (d, J=8.40 Hz, 2H), 7.30-7.38(m, 5H). Found: C, 62.49; H, 5.74; N, 4.59. C₂₉H₃₂N₂O₂×1.4 CF₃CO₂H×0.6H₂O has C, 62.51; H, 5.71; N, 4.58%.

Compound 11:N,N-Diethyl-4-[[2-(2-phenylethoxy)phenyl](piperidin-4-ylidene)methyl]benzamide

Using the same method as for COMPOUND 5 and using INTERMEDIATE 6 (0.202g, 0.435 mmol) and (2-bromoethyl)benzene (0.089 mL, 0.65 mmol) affordedCOMPOUND 11 as its trifluoroacetic acid salt (0.0514 g, 20%) and as awhite solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.10 (br t,J=7.1 Hz, 3H), 1.23 (br t, J=6.4 Hz, 3H), 2.23-2.37 (m, 2H), 2.46-2.60(m, 2H), 2.95-3.30 (m, 8H), 3.47-3.57 (m, 2H), 4.08-4.16 (m, 1H),4.24-4.32 (m, 1H), 6.91 (td, J=7.4, 0.8 Hz, 1H), 7.00 (d, J=8.2 Hz, 1H),7.06 (dd, J=7.4, 1.8 Hz, 1H), 7.11 (d, J=8.2 Hz, 2H), 7.18-7.28 (m, 5H),7.29 (d, J=4.5 Hz, 3H). Found: C, 65.06; H, 6.29; N, 4.61.C₃₁H₃₆N₂O₂×1.2 CF₃CO₂H×0.6 H₂O has C, 65.10; H, 6.28; N, 4.55%.

Compound 12:N,N-Diethyl-4-[{2-[(2-fluorobenzyl)oxy]phenyl}(piperidin-4-ylidene)methyl]benzamide

Using the same method as for COMPOUND 5 and using INTERMEDIATE 6 (0.205g, 0.441 mmol) and 1-(bromomethyl)-2-fluorobenzene (0.080 mL, 0.66 mmol)afforded COMPOUND 12 as its trifluoroacetic acid salt (0.243 g, 94%) andas a white solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.10(br t, J=6.7 Hz, 3H), 1.23 (br t, J=6.5 Hz, 3H), 2.33-2.46 (m, 2H),2.49-2.64 (m, 2H), 2.96-3.12 (m, 2H), 3.15-3.30 (m, 4H), 3.52 (br q,J=6.3 Hz, 2H), 5.02 (half of ABq, J=11.7 Hz, 1H), 5.15 (half of ABq,J=11.7 Hz, 1H), 6.98 (td, J=7.4, 1.0 Hz, 1H), 7.10-7.22 (m, 6H),7.24-7.41 (m, 5H). Found: C, 57.50; H, 4.94; N, 3.90. C₃₀H₃₃N₂O₂F×2.1CF₃CO₂H×0.1 H₂O has C, 57.54; H, 4.98; N, 3.92%.

Compound 13:4-[[2-(Cyclohexyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide

Using the same method as for COMPOUND 5 and using INTERMEDIATE 6 (0.199g, 0.429 mmol) and bromocyclohexane (0.079 mL, 0.64 mmol) affordedCOMPOUND 13 as its trifluoroacetic acid salt (0.0145 g, 6%) and as aslightly pink solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.11(br t, J=6.4 Hz, 3H), 1.17-1.61 (m, 9H), 1.66-1.82 (m, 2H), 1.93-2.03(m, 1H), 2.36-2.52 (m, 2H), 2.57-2.71 (m, 2H), 3.18-3.31 (m, 7H), 3.53(br q, J=7.2 Hz, 2H), 4.24-4.34 (m, 1H), 6.91 (td, J=7.4, 1.0 Hz, 1H),6.97 (d, J=8.4 Hz, 1H), 7.14 (dd, J=7.4, 1.8 Hz, 1H), 7.21-7.33 (m, 5H).Found: C, 59.65; H, 6.27; N, 4.36. C₂₉H₃₈N₂O₂×1.7 CF₃CO₂H×0.7 H₂O has C,59.59; H, 6.34; N, 4.29%.

Compound 14:N,N-Diethyl-4-[{2-[(3-methylbenzyl)oxy]phenyl}(piperidin-4-ylidene)methyl]benzamide

Using the same method as for COMPOUND 5 and using INTERMEDIATE 6 (0.204g, 0.440 mmol) and 1-(bromomethyl)-3-methylbenzene (0.089 mL, 0.66 mmol)afforded COMPOUND 14 as its trifluoroacetic acid salt (0.223 g, 87%) andas a white solid. Purity (HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.10(br t, J=6.5 Hz, 3H), 1.23 (br t, J=6.7 Hz, 3H), 2.32 (s, 3H), 2.40 (t,J=6.5 Hz, 2H), 2.52-2.68 (m, 2H), 2.98-3.10 (m, 2H), 3.13-3.30 (m, 4H),3.53 (br q, J=6.8 Hz, 2H), 4.96 (half of ABq, J=11.7 Hz, 1H), 5.04 (halfof ABq, J=11.7 Hz, 1H), 6.96 (td, J=7.4, 1.0 Hz, 1H), 7.05-7.10 (m, 2H),7.10-7.16 (m, 3H), 7.19-7.32 (m, 6H). Found: C, 63.76; H, 5.93; N, 4.38.C₃₁H₃₆N₂O₂×1.5 CF₃CO₂H has C, 63.84; H, 5.91; N, 4.38%.

Compound 15:N,N-Diethyl-4-[[2-(4-fluorophenoxy)phenyl](piperidin-4-ylidene)methyl]benzamide

To a mixture of INTERMEDIATE 6 (0.238 g, 0.512 mmol) and(4-fluorophenyl)boronic acid (0.143 g, 1.02 mmol) in dry CH₂Cl₂ (5 mL)was added Cu(OAc)₂ (0.0929 g, 0.511 mmol) and Et₃N (0.14 mL, 1.0 mmol).The resulting mixture was stirred at room temperature for 16 h. Thereaction was then diluted with methanol and concentrated in vacuo. Thecrude product was purified by silica gel column chromatography elutingwith 5:1 CH₂Cl₂:EtOAc. The purified product was dissolved in CH₂Cl₂ (10mL) and trifluoroacetic acid (1 mL) was added. After 2 h, the reactionwas concentrated in vacuo. The residue was purified by reverse phasechromatography, eluting with 10% to 90% acetonitrile in water containing0.1% trifluoroacetic acid. The appropriate fractions were concentratedand lyophilized from CH₃CN/H₂O to give COMPOUND 15 as itstrifluoroacetic acid salt (0.0504 g, 17%) and as a white solid. Purity(HPLC): >99%; ¹H NMR (400 MHz, CD₃OD) δ 1.08 (br t, J=6.7 Hz, 3H), 1.22(br t, J=6.5 Hz, 3H), 2.41-2.65 (m, 4H), 3.03-3.28 (m, 7H), 3.51 (br q,J=7.0 Hz, 2H), 6.69-6.75 (m, 2H), 6.86 (dd, J=8.2, 0.8 Hz, 1H),6.96-7.03 (m, 2H), 7.19 (td, J=7.5, 1.1 Hz, 1H), 7.22-7.36 (m, 6H).Found: C, 63.33; H, 5.69; N, 4.70. C₂₉H₃₁N₂O₂F×1.1 CF₃CO₂H×0.4 H₂O hasC, 63.39; H, 5.61; N, 4.74%.

Compound 16:N,N-Diethyl-4-[[2-(4-methylphenoxy)phenyl](piperidin-4-ylidene)methyl]benzamide

Using the same method as for COMPOUND 15 and using INTERMEDIATE 6 (0.189g, 0.407 mmol) and (4-methylphenyl)boronic acid (0.111 g, 0.813 mmol)afforded COMPOUND 16 as its trifluoroacetic acid salt (0.142 g, 61%) andas a white solid. Purity (HPLC): >96%; ¹H NMR (400 MHz, CD₃OD) δ 1.08(br t, J=6.6 Hz, 3H), 1.22 (br t, J=6.6 Hz, 3H), 2.27 (s, 3H), 2.44-2.65(m, 4H), 2.98-3.15 (m, 2H), 3.15-3.28 (m, 4H), 3.52 (br q, J=6.4 Hz,2H), 6.64 (d, J=8.6 Hz, 2H), 6.85 (dd, J=8.2, 1.0 Hz, 1H), 7.07 (d,J=8.0 Hz, 2H), 7.15 (td, J=7.5, 1.1 Hz, 1H), 7.22-7.32 (m, 6H). Found:C, 63.02; H, 5.72; N, 4.45. C₃₀H₃₄N₂O₂×1.5 CF₃CO₂H×0.2 H₂O has C, 62.99;H, 5.75; N, 4.45%.

1. A compound of formula I, a pharmaceutically acceptable salt thereof,diastereomers, enantiomers, or mixtures thereof:

wherein R¹ is selected from hydrogen, C₁₋₆alkyl-O—C(═O)—, optionallysubstituted C₁₋₆alkyl, optionally substituted C₃₋₆cycloalkyl, optionallysubstituted C₆₋₁₀aryl, optionally substituted C₂₋₉heterocyclyl,optionally substituted C₆₋₁₀aryl-C₁₋₃alkyl and optionally substitutedC₂₋₉heterocyclyl-C₁₋₃alkyl; R² and R³ are, independently, selected fromhydrogen, optionally substituted C₁₋₆alkyl and optionally substitutedC₃₋₆cycloalkyl; and A is selected from:

wherein R⁴ is selected from optionally substituted C₃₋₆alkyl, optionallysubstituted C₃₋₈cycloalkyl, optionally substituted C₆₋₁₀aryl, optionallysubstituted C₂₋₉heterocyclyl, optionally substitutedC₆₋₁₀aryl-C₁₋₆alkyl, and optionally substitutedC₂₋₉heterocyclyl-C₁₋₆alkyl; R⁵ is a divalent group selected fromoptionally substituted C₆₋₁₀ arylene, optionally substitutedC₂₋₉heterocyclylene, optionally substituted C₅₋₆cycloalkylene andoptionally substituted C₂₋₄alkylene, and D is selected from a singlebond, —CH₂—, —S—, —O—, —S(═O)—, —S(═O)₂—, —NH—, —NR⁶—, —C(═O)—, —CHR⁶—,and —CR⁶R⁷—, wherein R⁶ and R⁷ are independently C₁₋₆alkyl, C₆₋₁₀aryl orC₂₋₉heterocyclyl.
 2. A compound according to claim 1, wherein R¹ isselected from hydrogen, C₁₋₆alkyl-O—C(═O)—, optionally substitutedC₁₋₆alkyl, and optionally substituted C₃₋₆cycloalkyl; R² and R³ areethyl; R⁴ is selected from phenyl, C₃₋₅heterocyclyl, phenyl-C₁₋₃alkyl,C₃₋₅heterocyclyl-C₁₋₃alkyl, C₃₋₆cycloalkyl, andC₃₋₆cycloalkyl-C₁₋₃alkyl, wherein R⁴ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo, and iodo; R⁵ is a divalentgroup selected from ortho-phenylene, ortho-C₃₋₅heterocyclylene, andortho-C₅₋₆cycloalkylene, wherein R⁵ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo, and iodo; and D is selectedfrom a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂—, —NH—, and —C(═O)—. 3.A compound according to claim 1, wherein R¹ is selected from hydrogenand C₁₋₆alkyl-O—C(═O)—; R² and R³ are ethyl; R⁴ is selected fromphenyl-C₁₋₃alkyl, C₃₋₆cycloalkyl-C₁₋₃alkyl, C₃₋₆cycloalkyl, and phenyl,wherein R⁴ is optionally substituted with one or more groups selectedfrom methyl, fluoro, chloro, bromo and iodo; R⁵ is selected fromortho-phenylene, ortho-pyridylene, 1,2-cyclopentylene, and1,2-cyclohexylene; and D is selected from a single bond, —CH₂—, —S—,—S(═O)—, —S(═O)₂— and —C(═O)—.
 4. A compound according to claim 1,wherein R¹ is selected from hydrogen and t-butyl-O—C(═O)—; R² and R³ areethyl; R⁴ is selected from phenyl, methylphenyl, fluorophenyl,phenylethyl, cyclohexyl, fluorobenzyl, methylbenzyl, benzyl andcyclopentyl; R⁵ is ortho-phenylene; and D is selected from a single bondand —S—.
 5. A compound selected from:N,N-diethyl-4-[(2-phenoxyphenyl)-4-piperidinylidenemethyl]-benzamide;4-[[2-(benzyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethyl-benzamide;N,N-diethyl-4-(4-phenoxathiinyl-4-piperidinylidenemethyl)-benzamide;4-(4-dibenzofuranyl-4-piperidinylidenemethyl)-N,N-diethylbenzamide;4-[[2-(cyclopentyloxy)phenyl]-4-piperidinylidenemethyl]-N,N-diethylbenzamide;4-[[3-(benzyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide;N,N-diethyl-4-[[3-(2-phenylethoxy)phenyl](piperidin-4-ylidene)methyl]benzamide;4-[[3-(cyclopentyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide;4-[[3-(cyclohexyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide;N,N-diethyl-4-[(3-phenoxyphenyl)(piperidin-4-ylidene)methyl]benzamide;N,N-Diethyl-4-[[2-(2-phenylethoxy)phenyl](piperidin-4-ylidene)methyl]benzamide;N,N-Diethyl-4-[{2-[(2-fluorobenzyl)oxy]phenyl}(piperidin-4-ylidene)methyl]benzamide;4-[[2-(Cyclohexyloxy)phenyl](piperidin-4-ylidene)methyl]-N,N-diethylbenzamide;N,N-Diethyl-4-[{2-[(3-methylbenzyl)oxy]phenyl}(piperidin-4-ylidene)methyl]benzamide;N,N-Diethyl-4-[[2-(4-fluorophenoxy)phenyl](piperidin-4-ylidene)methyl]benzamide;N,N-Diethyl-4-[[2-(4-methylphenoxy)phenyl](piperidin-4-ylidene)methyl]benzamide;and pharmaceutically acceptable salts thereof. 6-7. (canceled)
 8. Apharmaceutical composition comprising a compound according to claim 1and a pharmaceutically acceptable carrier.
 9. A method for treatinganxiety or pain in a warm-blooded animal, comprising administering tosaid animal a therapeutically effective amount of a compound accordingto claim
 1. 10. A method for treating anxiety in a warm-blooded animal,comprising administering to said animal a therapeutically effectiveamount of a compound according to claim
 1. 11. A process for preparing acompound of formula I, comprising:

reacting a compound of formula II with A-B(OR⁸)₂:

wherein R¹ is selected from hydrogen, C₁₋₆alkyl-O—C(═O)—, optionallysubstituted C₁₋₆alkyl, and optionally substituted C₃₋₆cycloalkyl; R² andR³ are ethyl; X is selected from I, Br and Cl; R⁸ is selected from —Hand C₁₋₆alkyl; A is selected from:

wherein R⁴ is selected from phenyl, C₃₋₅heterocyclyl, phenyl-C₁₋₃alkyl,C₃₋₅heterocyclyl-C₁₋₃alkyl, C₃₋₆cycloalkyl, andC₃₋₆cycloalkyl-C₁₋₃alkyl, wherein R⁴ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo, and iodo; R⁵ is a divalentgroup selected from ortho-phenylene, ortho-C₃₋₅heterocyclylene, andortho-C₅₋₆cycloalkylene, wherein R⁵ is optionally substituted with oneor more groups selected from C₁₋₆alkyl, halogenated C₁₋₆alkyl, —NO₂,—CF₃, C₁₋₆ alkoxy, chloro, fluoro, bromo, and iodo; and D is selectedfrom a single bond, —CH₂—, —S—, —S(═O)—, —S(═O)₂—, —NH—, and —C(═O)—.